package main

import(
	"fmt"
)
func modify(a map[string]int){
	a["modify"] = 10000
}
func main()  {
	var a map[string] int
	if a == nil{
		a = make(map[string]int,16)
		a["stu01"] = 1000
		a["stu02"] = 2000
		a["stu03"] = 3000
		
		b := a
		b["stu03"] = 4000
		modify(a)
		fmt.Printf("after modify a:%v\n",a)

	}
	
}